PHYTOCHEMISTRY, CYTOTOXIC AND ANTIMICROBIAL ACTIVITIES OF SECONDARY METABOLITES FROM TREE BARKS AND ROOT CULTURES OF Morus macroura Miq. (ANDALAS)

• Main Author: Jasmansyah
• Format: Dissertations
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/37702
• Institution: Institut Teknologi Bandung

Morus plants, or known as “Mullbery”, consist of about 28 species and one of economically important genus in the family Moraceae. The distribution of this genus covers the tropical and subtropical regions of Asia, Europe, North America, South America, and Africa. This group of plants has an important relationship with silk industries because Morus leaves are used to feed silkworm?s. In addition to that, the fruits of Morus are edible, while its woods are a good source for home construction and furnitures. One of Morus species endemic to Indonesia is Morus macroura Miq. This species endemically growth in the west part of Sumatera, and is locally known as “Andalas”. Beside in this region, M. macroura can also be found in the southern part of China. Phytochemically there are significant differences in the content of secondary metabolites of M. macroura from China and Indonesia. The stems of M. macroura from Indonesia rich with a stilbene oxyresveratrol so that the plant is able to produce dimer stilbenes and a number of prenylated 2-arylbenzofuran derivatives. On the other hand, in addition to 2-arylbenzofuran derivatives, samples from China are a rich source of Diels-Alder adduct compounds. A part to that, reports on phytochemical studies of samples originating from tissue culture of this plant are still very rare. In the course to complete phytochemical study of Indonesian M. macroura, a phytochemical investigation of the tree bark of the plant has been undertaken. This research has also examined the chemical constituents of the root cultures of the plant. The isolated compounds from both samples were evaluated for their cytotoxicities against murin leukemia P-388 and their antibacterial properties. Samples of the tree barks of M. macroura were collected from Matur, West Sumatera.The root cultures of this plant were growh in the Natural Products Chemistry Laboratory FMIPA-ITB, Bandung. Isolation of the compounds was conducted via several stages of works, including extraction by maceration, fractionation and purification using various chromatographic techniques. The molecular structures of the isolated compounds were determined based on spectroscopic data, including UV, IR, NMR-1D (1H and 13C) and NMR-2D (COSY, HMQC, HMBC, NOESY) spectral data, and high resolution mass spectrometry (HRMS) data. Cytotoxicity test against P-388 murine leukemia cells were carried out by MTT [3-(4,5-dimetiltiazo-2-yl)-2,5-difeniltetrazolium bromide] assay, while antibacterial testings were carried out against two Gram-(+) (Staphylococcus aureus ATCC 25923 and Bacillus subtilis) and two Gram-(-) (Escherichia coli ATCC 25 922 and Proteus sp) bacteria using a microdilution assay. Based on these methologies, eleven compounds have been isolated from the tree barks and roots culture of M. macroura, ten of them were phenolic compounds of 2-arylbenzofuran, flavanone, orsinol, and Diels-Alder adduct derivatives, while another compound was a steroid. These compounds are moracin B (1), moracin C (3), moracin M (3), mulberrofuran K (4), norartocarpanone (5), mullberroside C (6), methyl 2,4-dihydroxy-3,6-dimethylbenzoate (methyl ?-orsinol carboxylate) (7), stigmasterol (8), moracin D (9), kuwanon J (10), and guangsangon E (11). Compounds 1-8 were isolated from the barks, and compounds 9-11 from the root cultures. Based on their structures, the tree barks of M. macroura tended to produce 2-arylbenzofuran derivatives, while the compounds from the root cultures were dominated by the adduct Diels-Alder type. Compounds 2, 5, and 7-9 were the first time to be isolated from this species, and compounds 1, 3, 4, 6, 10 and 11 were known compounds. In addition, methyl 2,4-dihydroxy-3,6-dimethylbenzoate (7) was the first benzoic acid derivative to be found in Morus. Results of cytotoxicity assay of the isolated compounds against P-388 murine leukemia cells showed that compound 4 was very active (IC50 0,58 ?g/mL), three compounds 3, 7, and 11 were active (IC50 2.1 to 4.0 ?g/mL), while seven other compounds 1, 2, and 5- 10 were inactive (IC50 > 4.0 ?g/mL). Based on these results, the 2-arylbenzofuran derivatives 3, 4 and 11 had higher cytotoxic activities than the flavanon 5 and steroid 8 derivatives. More specific, compounds 4 and 11 were the most active. On antibacterial assay, these eleven compounds showed various antibacterial properties against the four tested bacteria, with their MIC and MBC values were in the range of 3,125 – 100 µg/mL. Several compounds can be regarded as having strong antibacterials with MIC values < 10 µg/mL. Compounds 4, 10 and 11 exhibited strong antibacterial properties against S. aureus, E. coli and B. subtilis. Meanwhile, compounds 1 - 4, 6, 9 and 11 were also regarded to be strongly antibacterials. Based on their structures, the 2- arylbenzofuran derivatives 1, 4, 9 and 11 had also stronger antibacterial properties compare to the flavanon 5 and steroid 8 derivatives. Therefore, these compounds are potential as new sources of antibacterial compounds, particulary against resistance bacteria toward available antibiotic drugs. Based on these results we can conclude that this research has succesfully isolated eleven phenolic and nonphenolic compounds from the two samples of tree barks and root cultures of M. macroura. From the phytochemical study it can also be suggested that M. macroura from Indonesia produces less Diels-Alder adduct derivatives compare to its root cultures and the samples of the plant from Chinese origin which are more likely to produce these compounds. This study has also revealed cytotoxic and antibacterial activity of the eleven compounds 1-11, in which the Diels-Alder adduct mulberrofuran K (4) was the strongest cytotoxicity and showed a very high antibacterial activity against bacteria S . aureus. Thus, this compound can be recommended as a lead compound to be developed for antitumor and an antibacterial agents.